Volvo: fuel guage not working 1986 760 turbo, mass air flow meter, mass air flow

Question
1986 volvo 760 turbo
It seems to happen at random and sometimes for days at a time. but the fuel guage will simply turn off or never come on.  Also when filling up the fuel tank it is as if the pump doesnt know when to stop and has cause unintentional topping off of the tank to the point of spilling out.  Also is ther any way to increase fuel effieciency? ive only been getting a little more than 180mpg on a 12gallon tank when a 87 240dl was getting over 200 on 10 gallon.
Thank you for your time,
Nick

Answer
Nick,
You need to test the fuel sending system or have it checked. The sending unit or dash gauage, or the circurt board for the dash maybe going out or have loose connections. I would start by taking a ohm reading at the sender when the gauage does not work. If you get a reading then move to the dash and see if there is a reading there. See where the reading stops and repair or replace that piece/part.
As for the splash back look to see if the hose from filler neck to tank is kincked.
For fuel mileage have the system tested for proper fuel pressure and a good pressure regulator. Move on to tune ups as needed see if that helps. If the car runs rich at times and blows out black smoke you may have a Mass air flow meter problem. Don't overlook the fuel and air filters as well.